Human Interest

News to hand, we've just been informed that 2509 primary school and 2208 highschool students visited the JAMS exhibition during Science Unleashed. Add this to the 500 members of the public that dropped by on the family day and we have a grand total JAMS booth audience over 5000 people. The microbes should be very happy to get such attention!

A big thank you to all the volunteers who manned the JAMS exhibition booth at Science Unleashed over the last two weeks. In my humble opinion JAMS put together an exhibition booth that was about as engaging as an exhibition booth can get. Extra special thanks to Cathy Burke for organising the schedule. Top job! And finally the biggest thanks go to Michael Kertesz for pulling together the exhibition content. Hard to imagine it being done better. The booth was jam packed with interesting stories, ideas and seeds for future careers. We'll be at it again next year for sure. If you have ideas fresh in your mind for adding to the experience, send me an email


Mike Manefield (

Event Date: 
Wednesday, June 27, 2012 - 19:15 - 20:00
Faculty of Agriculture & Environment, University of Sydney, Sydney, NSW.

Sulfur cycling in the rhizosphere: the role of sulfatase and sulfonatase diversity.


Growth of healthy, high-yielding crop plants requires a stable input not only of nitrogen and phosphorus, but also of sulfur (S). Although S is naturally present in soils, it is usually bound in organic form as sulfate esters or sulfonates, which are not directly bioavailable to plants. Sulfur can be supplemented by addition of inorganic fertilizer, but most sulfate for plant nutrition is provided by microbial turnover of organically-bound sulfur. To identify the rhizosphere organisms responsible for this turnover, we focused on the key genes atsA, which encodes arylsulfatase, and asfA, which is required for aryldesulfonation. Functional T-RFLP analysis was used to analyse atsA diversity in a range of agricultural and natural soils, and clear atsA community differences associated with land use and soil/bedrock types were observed, which were mirrored in the arylsulfatase activity of the cultivable fraction of the population. Soil arylsulfatase activity is routinely assayed as a measure of soil health, but these data highlight the need for detailed studies on arylsulfatase gene diversity in the soil. Sulfonatase diversity was measured in rhizospheres of field-grown wheat plants and in a sulfate-limited Agrostis-dominated grassland, and the effect of adding sulfate in long-term or short-term treatments was tested. Functional asfA community analysis showed that desulfonation genes from both wheat and Agrostis rhizospheres were dominated by Variovorax and Polaromonas species. This distribution of taxa was also found in a cultivation-dependent analysis, and these genera appear to be key players in rhizosphere sulfonate transformations in several environments. Increasing our understanding of the rhizosphere microbes that catalyse soil organosulfur turnover will allow us to develop management practices to maximize soil sulfur availability, and minimize the costs associated with fertilization.

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